Contactor for moisture meters



R. S. HART CONTACTOR FOR MOISTURE METERS March 6, 1945.

Filed June 19, 1941 mvzu-rbn Rqymanl Jpeers H v ATTORNEY Patented Mar. 6, 1945 UNITED STATES PATENT OFFICE coNmo'ron-ronmorstronn METERS Raymond Sp'e'ers Hart, Brooklyn, N. Y.

Application June19, 1941, Serial-No. 398,709

4 Claims. This invention relates to improvements in contactors for moisture meters and particularly to contactors for measuring the moisture of gran uiar materials; 7

Heretofore it wa necessary, when it was desired to measure the-moisture content of such materials as flour, etc to apply the slow and cumbersome method of the oven-and sc'ale whereby a sample is weighed before and after drying and the moisture content is computed as a; percentage of the total weight from thedifierence in weight before and afterdrying. It has been found, however; that by the use of a special contactor it is possible to quickly measure the moisture content by the conductivity of the material using a meter such as disclosed in my Patent No. 2,183,333 dated December 12, 1939. The present invention serves this purpose as it will be shown hereinafter and it furnishes new and unique means for the quick determinationof the moisture as well as forthe easy handling of the materials to be tested. 1

important object of the invention i to provide a contactor with two electrodes, one of which is Well insulated from the other, and which I may be connected to a sensitive meter.

Another object of my invention is to provide a contactor having one electrode removable and formed in the shape of a sampling spoon wherein the sample to be tested may be placed by dipping the spoon directly into, for instance, a bag of flour or other container.

A further, object of my invention is to provide a contactor of the lever type providing means for obtaining repeatedly the same pressure between the electrodes and being easily operable by the handle of the one electrode.

Other objects and advantage of the invention will be apparent during the course of the following description.

In the accompanying drawing, forming a part ,of this specification, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation of a moisture meter contactor embodying my invention,

Figure 2 is a view along line 22, in Figure 1.

Figure 3 is a plan view of the combined sample spoon and electrode,

Figure 4 is a plan view of the compound lever,

' and,

Figure 5 is a section along line 5-5 in Fig. 1. In the drawing, wherein for the purpose of illustration, is .shown a preferred embodiment of my invention, the numeral l0 designates the and, therefore, an exceedingly high insulation resistance. To the bottom side of the insulator i6 is fastened a metal disc having a small hub I8 and being free to swivel on the fastening screw IS. The metal disc formsthe one electrode from which a wire is connected to the grid of a sensitive vacuum tube'voltmeterinstrument such as disclosed in my patent mentioned supra.

The other electrode consists of the cup-shaped metallic part 20 which is fastened on a bar 2| and; which has a transverse groove 22 which fits over the nose 23 of the compound lever 24. The removable electrode 20 with arm 2| is shown in plan View in Figure 3 and the lever 24 is shown in plan view in Figure 4. The lever 24 is forked at one end and its two forked ends 25 and 26 are pivoted to the C-clamp In by the pins 21.

The lower jaw of the C-clamp has a cylindrical body 28 which is bored out as shown in Figure 5, in cross-section. The hollow section of the cylindrical portion 28 contains the vertical push rod 29 which is-journalled in a bearing in the upper end of the body 28 and also in a bearing in the bottom nut 30. The push rod 29 has a fixed shoulder 3| and between this shoulder BI and the bottom nut 30, is located a heavy coil spring 32. The tension of the spring 32 may be adjusted by turning the bottom nut 30 which has two holes 33 for the insertion of a wrench.

The operation of my invention is as follows:

Once the tension of spring 32 is adjusted and the meter is calibrated for a certain granular material, it is only necessary to connect disc I! to the grid terminal of the meter while the body of the contactor is connected to the ground terminal. The lower contactor cup with handle 2| may then be removed and dipped into the material to be tested whereby the cup is filled with a suitable sample. The handle 2| with cup 20 is again inserted into the contactor and the handle 2| is brought downward with a pressure directed,

as shown by the arrow in Fig. By applying a sufficient pressure on handle 2|, the cup 211 will 2| together with the lever 24 will form a compound lever arrangement which will force the end of the lever 24 down and will move the push rod 29 with shoulder 3! down against the pressure of spring 32. After a comparatively small movement of the lever 2|, the pressure between disc I! and cup is then that which is caused by I the spring 132 and the pressure will not change very much regardless of whether the lever is moved a little more or less as long as the spring 32 is fully engaged. At this point the meter reading is made and consistent readings will be possible because the pressure is maintained at a figure which will be the same repeatedly for every measurement made because of the preloading of spring 32 and due to the face that said spring is just barely engaged. In this manner a substantially constant pressure is obtained, provided lever 2| is moved only until 3! just leaves stop 28 so that full spring pressure is obtained. V

In addition to flour and similar materials, there are a number of other industrial products which may be tested similarly and to great advantage by the use of this contactor. Due to the fact that quite often a great number of tests have to be made at one time, the present contactor affords the possibility of making quick determinations without many and elaborate operations.

It is to be understood that the forms of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to Without departing from the spirit of my invention or the scope of the subjoined' claims.

Having thus described my invention I claim:

1. In an instrument for testing comminuted material, a frame having a depending insulated electrode, a spring controlled push rod below the electrode, means pivoted on said frame and having a portion resting on said rod, and manipu- 2,s7o,css

lable means adapted to rest on the first means and having a cup-shaped electrode for holding material below and in contacting relation with ceptacle for holding material to be tested below and in contacting relation with the first mentioned electrode, said member adapted to be removably seated on the lever.

3. A testing device for comminuted material comprising in combination a frame having thereon an upper depending insulated electrode, a

lower cylinder rigid with the frame and having therein a spring controlled rod with an upper end below the electrode, a normally horizontal lever pivoted on the frame and resting on said end, the

lever providing a space below the electrode, a

manipulable member including a handle and having a portion for enterin said space, and another electrode forming a receptacle for mate rial and carried by said portion below the upper electrode. I

4. A testing device for comminuted material comprising in combination a frame having upper and lower arms and a lateral attaching member, an insulated electrode carried by the upper arm, a housing having top and bottom apertures and rigid with the lower arm, a rod movable in the apertures and having an upper projecting end, spring means controlling said rod, a lever pivoted on the frame and resting on said end, manipulable means removably seated on the lever, and an electrode forming a sampling container and disposed on the last mentioned means below and adjacent the upper electrode.

RAYMOND SPEERS HART. 

